1. Field of the Invention
The present invention relates to a method and apparatus for making a modified amorphous glass material which is either a metallic, dielectric or a semiconductor glass material.
2. Description of the Prior Art
Heretofore, it has been known to make metallic glass materials with a technique that is referred to as metal spinning. In practicing such technique, a movable substrate, i.e., a rotating wheel, made of a highly conductive metal is positioned beneath a nozzle at the outlet of a reservoir of liquid metal or metal alloy. The wheel, because of its mass and because of the significant difference in temperature between the molten metal and the ambient temperature of the wheel, need not be cooled in order to provide a cold moving substrate relative to the molten metal. The wheel is typically between 6" and 10" (15.24 and 25.40 centimeters) in diameter and is rotated at a rotational velocity of between 1,000 and 5,000 rpm thereby to obtain a linear velocity, at the point of contact of the metal with the cylindrical periphery of the wheel, of 32.81 to 65.62 feet per second (1,000-2,000 centimeters per second).
Upon contacting the wheel, the molten metal is cooled at a quenching rate of 10.sup.4 to 10.sup.8 .degree. C. per second and comes off the wheel in a ribbon of metallic amorphous glass. Such amorphous metal glass material has been found to have a number of unique properties such as better ductility and elasticity and the ability of the material to handle reverses in magnetic field with much lower losses than obtained with crystalline materials.
Further information on making amorphous metal glasses can be found in the following articles and book:
"On the uniformity of amorphous metal ribbon formed by a cylindrical jet impinging on a flat moving substrate" by T. R. Anthony and H. E. Cline, Journal of Applied Physics, February 1978, page 829;
"Metallic Glasses" by Praveen Chaudhari, Bill C. Giessen and David Turnbull, p. 98, Vol. 242, No. 4, Scientific American, April 1980;
"Metallic Glasses" by John J. Gilman, Science, p. 856, Vol. 208, May, 1980; and
Metallic Glasses published by the American Society for Metals, 1976, Meadowpark, Ohio 44073.
It has also heretofore been proposed to make amorphous semiconductor materials such as by vacuum deposition, e.g., sputtering, vapor deposition, or glow-discharge, etc. Further, it has been proposed to make a modified amorphous semiconductor material which has a modifier material therein for providing to so-called modified amorphous semiconductor material in which the electrical conductivity and other desired parameters can be controlled. Examples of such methods for making a modified or unmodified amorphous semiconductor material are disclosed in: U.S. Pat. No. 4,177,473 issued to S. R. Ovshinsky for: AMORPHOUS SEMICONDUCTOR MEMBER AND METHOD OF MAKING THE SAME; U.S. Pat. No. 4,177,474 issued to S. R. Ovshinsky for: HIGH TEMPERATURE AMORPHOUS SEMICONDUCTOR MEMBER AND METHOD OF MAKING THE SAME; and U.S. Pat. No. 4,178,415 issued to S. R. Ovshinsky and K. Sapru for: MODIFIED AMORPHOUS SEMICONDUCTORS AND METHOD OF MAKING THE SAME.
As will be explained in greater detail hereinafter, the method and apparatus of the present invention differ from the teachings of the prior art by providing a modifying element(s) which can be introduced into the amorphous matrix so that it can enter the matrix with its own independent, separately controllable, quench rate. Thus the modifying element(s) can be frozen into the matrix so as not only to enter the primary bonding of the material to become part of the alloy, but most importantly to be frozen into the alloy in a non-equilibrium manner. This essentially duplicates the film making processes described in the above patents, so that the material parameters of the solid bulk material alloy are relatively independently controllable; i.e., in alloy materials with a substantial band gap, an electrical activation relatively independent of the gap. This expands the unique advantages of the modification processes to material thicknesses substantially greater than so-called films.
Such modifying element(s) can be added by providing relative motion between the matrix and the modifying element(s), such as by providing one or more additional streams such as a second stream of material, directed from a second nozzle, in a metal spinning apparatus, the second nozzle being at the outlet of a reservoir of a fluid modifier material. Such second nozzle is arranged to direct the fluid modifier material toward the substrate in a stream which converges with the stream of metallic or semiconductor host matrix material being directed onto the substrate from a first nozzle at or before the host material makes contact with the substrate. In this way, a modified amorphous metallic or semiconductor glass material is made in which the optical and electrical transport properties of the material formed by the method can be controlled and a controlled number and type of bonding points can be provided in the modified amorphous material.
Further, as will be explained in greater detail hereinafter, the modified amorphous glass materials made according to the teachings of the present invention have different properties that are advantageous. For example, a modified glass material having a large number of bonding points can be utilized for catalytic activity as well as for storing gases, the atoms of which bond to the controlled number and type of bonding points in the material. On the other hand, a modified amorphous semiconductor material in which the optical and electrical transport properties can be controlled can be utilized for various solid state semiconductor devices, for example, thermoelectric devices or devices having other desired properties, such as where the control of the density of states at the Fermi level can effect collector carrier activity.